Adjustable catch for windows, doors, shutters and the like

ABSTRACT

An adjustable catch for windows, doors, shutters and the like of the type having a catch bar pivotally mounted at one end in a catch bracket and capable of being moved into and out of engagement with a separate catch fitting. The catch bar has disposed on at least one long side thereof an elongated groove presenting a number of distinct latching positions, and located at one end of the bar is a wedge-shaped portion. The separate catch fitting has at least one laterally extending latching element intended to engage the latching positions along the bar and which is sprung back by the wedge-shaped portion when engaging the catch bar with the catch fitting and which snaps into the groove, when pressure from the wedge-shaped portion is removed. Accidental removal of the latching element from the groove is prevented by raised surfaces extending peripherally of the groove, while at least one recess is formed in the raised surfaces to permit intentional withdrawal of the latching element from the groove.

United States Patent Asp et a1.

ADJUSTABLE CATCH FOR WINDOWS, DOORS, SHUTTERS AND THE LIKE Inventors: Ivar Alvar Asp, Storbergsliden 15;

Alf Herder Sundberg, Blockvagen 19, both of Sollentuna, Sweden Filed: May 19, 1972 Appl. No.: 255,034

Foreign Application Priority Data May 25, 1971 Sweden 6721/71 References Cited UNITED STATES PATENTS 8/1912 Cottle 292/269 1/1925 FOREIGN PATENTS OR APPLICATIONS 3/1936 Great Britain 292/270 2/1935 Great Britain 292/266 Landine 292/268 x UUU [ Apr. 30, 1974 Primary Examiner-Richard E. Moore Attorney, Agent, or Firm-Eric H. Waters [57) ABSTRACT I An adjustable catch for windows, doors, shutters and Q the like of the type having a catch bar pivotally mounted at one end in a catch bracket and capable of being moved into and out of engagement with a separate catch fitting. The catch bar has disposed on at least one long side thereof an elongated groove presenting a number of distinct latching positions, and located at one end of the bar is a wedge-shaped portion. The separate catch fitting has at least one laterally extending latching element intended to engage the latching positions along the bar and which is sprung back by the wedge-shaped portion when engaging the catch bar with the catch fitting and which snaps into the groove, when pressure from the wedge-shaped portion is removed. Accidental removal of the latching element from the groove is prevented by raised surfaces extending peripherally of the groove, while at least one recess is formed in the raised surfaces to permit intentional withdrawal of the latching element from the groove.

17 Claims, 7 Drawing Figures C U JUUU 3 1 ADJUSTABLE CATCH FOR WINDOWS, DOORS, SHUTTERS AND THE LIKE The present invention relates to an adjustable catch for windows, doors, shutters and the like, comprising a catch bar which is pivotally mounted at one end thereof and which is arranged for longitudinal movement relative to a separate catch unit and is capable of being latched thereto. The catch unit is provided with at least one latching tooth or stud and extending along the catch bar is at least one groove in which is disposed a number of latching positions and in which the latching tooth engages, when the catch is operative, the catch unit being arranged for longitudinal movement relative to the groove and to be locked in desired latching positions therealong.

Many different variations of window catches of the aforementioned type are known which enable a window, shutter, door or like hinged element to be opened, either in a continuous movement or in stages, and latched in the opened position by means of a catch member cooperating with latching stations disposed along the catch bar.

Since it is often desired to release the catch bar from the catch means in general, so that the window etc. can be opened to a wider extent than that permitted by the catch bar when occupying its operative window latching position, many of the known catches are designed so that the catch bar can be easily disconnected from its associated co-acting catch unit.

As a result of the high rate of accidents caused by falls from highly situated windows, and especially in regard of childrens safety in this respect, the need is shown for a window catch of the aforedescribed type with which a window, for example, can only be latched opened to a limited extent and which is virtually safe against release by children, and which at the same time permits the window to be opened to varying degrees within the maximum opening range allowed by the catch and which can be securely latched in such positions.

The primary purpose of a catch constructed to permit a window or the like to be latched open to a limited extent is to permit the window to be kept open while protecting children, particularly very young children, from the hazard of a widely open window or a window which may open to a wider extent inadvertently. A window catch which totally prevents a window from being opened to its full extent, however, is not altogether suitable, since there are many occasions which require a window, for example, to be opened to the maximum extent permitted by its hinges, such as when cleaning the window for instance. Consequently, a catch of the type envisaged should provide means which, although being practically unmanipulatable by younger children, permit relatively easy disengagement and engagement of the catch bar from and with its cooperating catch member by older persons.

While such a catch must be effective from the aspect of safety, it must also be possible to engage and disengage the catch bar with and from its associated coacting catch member with as little force and as easily as possible, so that the catch can be manipulated by handicapped persons without difficulty.

An object of the present invention is therefore to solve the aforementioned problems and to eliminate the disadvantages associated with known catch constructions.

. Accordingly, the catch of the present invention is mainly characterized in that the latching tooth is yieldingly arranged in the catch unit in a manner such that the catch bar can be swung into the catch unit from a non-engaged position by positively urging the latching tooth to one side with the catch bar, until the latching tooth springs back into the groove disposed along the bar, the groove engaging the latching tooth and preventing accidental dislodgement of the tooth therefrom in all relative positions of the catch unit along the bar.

The invention will now be described in more detail with reference to an embodiment thereof illustrated in the accompanying drawings, in which FIG. 1 illustrates in horizontal section a framework extending circumferentially around a door opening, window opening or the like and a door, window shutter, sash or the like hinged thereto, and an adjustable catch constructed in accordance with the invention adjusted to one of its latching positions, FIG. 2 illustrates in larger scale and in plan view a catch bar according to the invention pivotally mounted in a bracket structure, FIG. 3 is a crosssectional view taken along line IlIIII in FIG. 2, FIG. 4 is a cross-sectional view taken along line IVIV in FIG. 2, FIG. 5 is a cross-sectional view taken along line VV in FIG. 2, FIG. 6 is a front view of a catch member cooperating with the catch bar, and FIG. 7 illustrates the same catch member as that in FIG. 6, seen partially in section and from the right.

In the drawing, the reference numeral 10 indicates generally a frame surrounding a window opening, door opening etc., and the reference numeral 11 a sash, casement or the like, the latter being pivotally mounted to one vertical side of the frame 10 by means of hinges l2.

Secured to the bottom portion of the frame 10 in a known manner is a pivot fitting 13, in which a catch bar 14 constructed in accordance with the invention is pivotally mounted about a vertically extending pin 15. The

catch bar 14 is illustrated substantially in its widest latching position, inserted in a catch unit 16 attached to the bottom portion of the sash, casement or the like.

In accordance with the invention, the catch bar 14 is normally latched in the catch unit 16 in a manner such that the window 11 or the like can only be swung away from the frame through a maximum angle, e.g. the angle a corresponding to a maximum horizontal distance A to which the window can be latched open, this distance naturally being dependent on the distance of the pivot fitting l3 and pin 15 from the hinge l2 and which can thereforebe adjusted when mounting the adjustable catch to the window etc. Normally, this distance is selected so that the window etc. can be opened to a satisfactory extent, without creating a hazard to young children.

The catch bar 14 has disposed along the length thereof a number of latching positions, to be described hereinafter with reference to FIG. 2, to permit the window to be opened to different angles within the maximum angle a.

The preferred embodiment of the adjustable catch according to the invention, illustrated in full lines in FIG. 1, shows the catch bar in one of its latching positions, more specifically in the outermost latching position. The basic concept of the invention is to provide a practical catch which permits manipulation and adjustment thereof between the different latching positions while at the same time rendering it practically impossible for young children to disengage the catch bar from the catch member and thereby enable the window to be opened to its fullest extent with the associated accident risk.

Since, as before mentioned, a catch which only permits a window or the like to be opened to a limited extent is not fully acceptable in practice, the catch of the present invention is also provided with means for engaging and disengaging the catch bar with and from the catch unit, which requires a certain degree of dexterity on the part of the person manipulating the catch, so that it is practically impossible to release the catch bar from the catch unit accidently.

Consequently, the present invention also includes such a means with which, under certain conditions, the catch bar can be disengaged from the catch unit and swung to one side to take the position shown in dotted lines 17 in FIG. 1.

The preferred embodiment of the invention will now be described in more detail with reference to FIGS. 2 7. FIG. 2 illustrates the catch bar 14 in larger scale. As with the catch bar in F IG. 1, the catch bar 14 illustrated in FIG. 2 is pivotally mounted about the pin 15 in the pivot fitting 13. The bar has an arcuate, knee portion 18 to which a relatively long, straight bar portion is connected, the straight portion of the bar being terminated with a finger grip 19 provided to facilitate movement of the bar.

As will be seen from FIGS. 2 5, the catch bar 14 is provided on opposing sides thereof with a longitudinally extending recess or groove 20 defined along one long side thereof and adjacent the finger grip 19 by raised edge portions or shoulders 21 and 22, and along the other long side by a raised comb-like wall 23 with the tooth-like configurations thereof rounded, as shown at 24. The spaces between the teeth of the comb-like wall 23 form latching positions 25 for the catch bar 14 relative to the catch unit. Located at the entrances to the latching positions are thresholds 26, the height of which is less than the height of the comblike wall 23.

Further, it may be mentioned that in the illustrated embodiment no transversally extending, raised groove terminating shoulder is provided at the end of the grooves 20 located adjacent the arcuate, knee-like portion of the catch bar, since the manner in which the catch is mounted renders such provision unnecessary. However, the provision of such a groove terminating shoulder can be made at said end of the catch bar in order to fully enclose the groove 20.

As will be seen from FIGS. 1, 2 and 3, there is arranged in the extension-of the groove defining edges, at

the junction between the arcuate portion 18 and the straight portion of the catch bar a wedge-shaped or plough-shaped member 27. In accordance with the invention, the free end 27a of the wedge 27 is substantially located in a plane situated at a distance from an axial plane extending parallel therewith through the axis of rotation, i.e., the center axis of the pin 15, in a direction towards the straight catch bar portion. It has been found in practice that the end 27a of the wedge 27 should be located in a plane which does not pass through the pin but which is located at an adjustable distance therefrom with respect to the latching means of the catch unit. Further, it can be mentioned that in the illustrated example the thickness of the arcuate or knee-shaped portion 18 is equal to the distance be tween the bottom surfaces of the two grooves 20, wherewith the grooves at the same time have a form similar to an elongated pocket with the pocket opening located at said junction.

Referring to FIGS. 2 and 4, it will be seen that the raised edges 21 are broken at one position therealong by recesses 28, each of which presents a threshold portion 29. It will also be seen from the Figures that the recesses 28 are placed substantially opposite a tooth-like projection 30 of the comb-like structure 23, the lateral width of the tooth-like member 30 being slightly greater than the width of the remaining tooth-like members 24, for a reason hereinafter described.

The catch unit 16 co-acting with the catch bar is illustrated separately in FIGS. 6 and 7 and comprises substantially a block-like portion 31 having screw holes 32 disposed therein, the screw holes being'countersunk on both sides thereof to enable the catch unit, and similarly the catch bar 14 and pivot fitting 13, to be mounted on windows, doors and the like which open to the left and to the right. For the same reason, there is arranged through a symmetry plane extending through the block 31 a stirrup-shaped member presenting an open gap 33. As will be seen from the Figures, the two limbs 34 and 35 of the stirrup-shaped member are each provided with a latching means, which in the illustrated embodiment comprises pin-shaped members 36 and 37 of circular cross section. The two pins define therebetween the effective width of the gap 33 to a magnitude which, when the catch bar of the catch illustrated in FIG. 1 is inserted in the gap presented between the limbs of the catch unit and the pins are caught in their respective groove 20 in the catch bar, contributes to preventing the pins from leaving the grooves. The cross section of the pins is so adjusted that the pins are able to pass into and move along the grooves, and are capable of being moved into the latching positions along the groove and also capable of passing through respective recesses 28 located in the raised edge portions 21.

The width of the gap 33 substantially coincides with the maximum thickness of the catch bar, whereby the bar can be received between the limbs 34 and 35 defining the gap with at least a certain degree of clearance. In the preferred embodiment, the arrangement of the catch unit is such that at least one of the latching pins can be moved resiliently to enable the catch bar to be swung into and out of the gap 33.

Thus, with the embodiment illustrated in FIG. 1, when the catch bar 14 is to be engaged with the catch unit 16, the window 11 is swung towards a closed position and the catch bar moved from the position 17 shown in dotted lines, until the gap 33 and the pins 36 and 37 are located in front of the wedge-shaped member 27 (see also FIGS. 2 and 3), whereafter the wedge shaped member 27 forces at least one of the latching pins to yield, until the edges 38 of the wedge-shaped member 27 have completely passed the pins and the pins are caught in the grooves 20 behind the member 27. With a preferred embodiment, the co-acting elements of the catch are so dimensioned and oriented that the pins automatically snap into the grooves, when the window is closed.

When wishing to disengage the catch bar from the catch unit, the window or like element is opened to a position in which the pins 36 and 37 are in registry with the recesses 28 and the modified tooth-like member 30, in which position the catch bar is turned in a manner such that while guiding the pins past the members 30 the pins 36 and 37 when reaching a certain position are able to leave the grooves 20 through the recesses 28.

To restrict the ease with which the pins are able to leave the groove, threshold members 29 (FIG. 4) are arranged, the threshold members forcing the pins to yield while producing a certain resistance to the twisting of the pins out of the groove and through the recesses 28. Thus, in order to separate the catch bar from the catch unit it is necessary to place the pins 36 and 37 and the recesses 28 in a predetermined relationship with each other and to use an extra degree of force in order to move the pins through the recesses 28.

The same principle is used with the threshold members 26 for inserting the pins into and out of the latching positions 25.

Although the illustrated embodiment of the adjustable catch is preferred for the simple reason that the same catch can be used efficiently for both right-hand and left -hand windows, by reversing the position of the elements, it also lies within the purview of the invention to construct the catch solely for either a right-hand or a left-hand window, door or like element. In this instance, a groove is required on only one side of the catch bar, suitably its underside, and one single pin, suitably the pin 37 on the limb member of the catch unit 31.

With regard to the arrangement of the pins, the stirrup structure 32 as a whole or at least one of the limb members 35 or 34 may be resilientand may be made, for example, from a resilient material such as a plastic material. Further, all or certain portions of the adjustable catch may also be made of a plastic material.

Finally, each pin may comprise a separate portion made from an appropriate material or may be formed integrally with the catch unit.

The invention is not restricted to the described and illustrated embodiment, but may be modified within the scope of the accompanying claims.

We claim:

1. An adjustable catch assembly for windows, doors, shutters and like openingelements, said catch assembly comprising a catch bar having opposite ends, one of which is pivotally mounted on a fixed frame, a separate catch unit mounted on said opening element, said catch bar being arranged for longitudinal movement relative to said separate catch unit and being capable of being latched to said unit, said catch unit including at least one latching element, the catch bar having at least one groove extending therealong, means on said catch bar defining a number of longitudinally spaced latching positions at which the latching element lockably engages the catch bar, when the catch bar is latched to said catch unit, said catch unit being arranged for longitudinal movement relative to the groove and capable of being locked in desired latching positions along said groove, wall means bounding said groove to prevent release of the latching element from said groove, said latching element being yieldingly arranged in said catch unit, means arranged adjacent said wall means such that the catch bar can be swung into the catch unit from a non-engaged position by positively urging the latching element away from the catch bar, until the latching element springs back into the groove disposed along the bar, the groove then being engaged by the latching element which is prevented from being accidentally dislodged therefrom by said wall means in all relative positions of the catch unit along the catch bar, and means disposed on said wall means, proximate the groove and independent of the means by which the latching element engages the catch unit, for releasing the latching element from the catch bar.

2. An adjustable catch assembly according to claim 1 wherein the groove in the catch bar is provided on at least one long side thereof located in the pivoting plane of said bar, said groove extending longitudinally and defining a row of said latching positions, said wall means including a longitudinally raised edge portion which serves to prevent accidental disengagement of the latching element of the catch unit with the groove along which it is arranged to move, the length of the longitudinally extending raised edge portion of the groove being such as to effectively engage the latching element in the groove in all relative positions therealong, and a transversally extending raised edge port-ion bounding the groove to form a stop for the latching element, when the opening element is opened to the maximum extent permitted by the catch assembly.

3. An adjustable catch assembly according to claim 1 wherein the catch unit has an open gap for receiving the catch bar, respective limb portions on said catch unit facing respective grooves provided in the catch bar, one of said latching elements being mounted on each limb portion and having such length as to restrict the effective width of the gap to a magnitude less than the height of the wall means which contributes to preventing the latching elements from leaving the grooves, the cross section of the latching elements being so adjusted as to permit said elements to slide in the groove and to be inserted into the latching positions.

4. An adjustable catch assembly according to claim 1 wherein the groove extending along the catch bar is defined on one long side by a comb-like wall including adjacent .spaced teeth facing inwardly towards the groove and forming the latching positions between adjacent, teeth. I

5. An adjustable catch assembly according to claim 3 wherein the gap between the limb members of the catch unit has a width which corresponds substantially to the thickness of the catch bar.

6. An adjustable catch assembly according to claim 1 wherein said means enabling the catch bar to be engaged by the latching element includes a wedge-like member on said catch bar positioned to force the latching element resiliently when inserting the catch bar into said gap, until said latching element has passed into the groove.

7. An adjustable catch assembly according to claim 6 wherein said wedge-shaped member is located adjacent the end of the catch bar which is connected to the fixed frame, said wedge-shaped member terminating substantially in a plane extending parallel with a plane passing through the pivotal axis of the catch bar to said frame and located at a distance from said plane in a direction towards the other end of the catch bar.

8. An adjustable catch assembly according to claim 1 wherein said means for releasing the latching element from the catch bar is constituted by a recess in said wall means through which the latching element can pass to enable the catch bar to be disconnected from the catch unit.

9. An adjustable catch assembly according to claim 8 comprising a threshold at the bottom of the groove which renders it necessary for the latching element to yield in order to leave the groove through the recess so as to release the catch bar from the catch unit.

10. An adjustable catch assembly according to claim 4 in which the catch bar is provided with one said groove in two opposing long sides thereof, said wall means including a raised portion opposite each of the comb-like walls for said two grooves, said catch unit having an open gap for receiving the catch bar, respective limb portions on said catch unit facing respective grooves provided in the catch bar, one of said latching elements being mounted on each limb portion and having such length as to restrict the effective width of the gap to a magnitude less than the height of said wall means to prevent the latching elements from leaving the grooves, the cross section of the latching elements being so adjusted as to permit said elements to slide in the groove and to be inserted into the latching positions.

11. An adjustable catch assembly according to claim 10 wherein said means for releasing the latching element from the catch bar is constituted by a recess in each said raised portion enabling passage therethrough of the latching elements for disconnection of the catch bar for the catch unit.

12. An adjustable catch assembly according to claim 1 1 wherein said means enabling the catch bar to be engaged by the latching element comprises a wedgeshaped member on said raised portions to enable engagement of the catch bar with the catch unit.

13. An adjustable catch assembly according to claim 12 wherein the catch bar comprises a knee-shaped portion and a straight portion, which form an angle with each other, the knee-shaped portion having a pivotal connection to the fixed frame and holding the wedgeshaped member at a distance from said pivotal connection to enable the wedge-shaped members to be engaged with respective latching elements.

14. An adjustable catch assembly according to claim 4 comprising thresholds on said catch bar at the entrances of said latching positions between adjacent teeth of the comb-like wall which force the latching element to yield laterally when said element is moved into said latching positions.

15. An adjustable catch assembly according to claim 1 wherein the catch bar and the catch unit are made from a plastic material.

16. An adjustable catch assembly according to claim 1 wherein said latching element is integrally formed with the catch unit and made from the same plastic material, said plastic material being resilient.

17. An adjustable catch assembly according to claim 1 wherein said latching element has a squared-off cross section to oppose disengagement thereof from the catch bar. 

1. An adjustable catch assembly for windows, doors, shutters and like opening elements, said catch assembly comprising a catch bar having opposite ends, one of which is pivotally mounted on a fixed frame, a separate catch unit mounted on said opening element, said catch bar being arranged for longitudinal movement relative to said separate catch unit and being capable of being latched to said unit, said catch unit including at least one latching element, the catch bar having at least one groove extending therealong, means on said catch bar defining a number of longitudinally spaced latching positions at which the latching element lockably engages the catch bar, when the catch bar is latched to said catch unit, said catch unit being arranged for longitudinal movement relative to the groove and capable of being locked in desired latching positions along said groove, wall means bounding said groove to prevent release of the latching element from said groove, said latching element being yieldingly arranged in said catch unit, means arranged adjacent said wall means such that the catch bar can be swung into the catch unit from a non-engaged position by positively urging the latching element away from the catch bar, until the latching element springs back into the groove disposed along the bar, the groove then being engaged by the latching element which is prevented from being accidentally dislodged therefrom by said wall means in all relative positions of the catch unit along the catch bar, and means disposed on said wall means, proximate the groove and independent of the means by which the latching element engages the catch unit, for releasing the latching element from the catch bar.
 2. An adjustable catch assembly according to claim 1 wherein the groove in the catch bar is provided on at least one long side thereof located in the pivoting plane of said bar, said groove extending longitudinally and defining a row of said latching positions, said wall means including a longitudinally raised edge portion which serves to prevent accidental disengagement of the latching element of the catch unit with the groove along which it is arranged to move, the length of the longitudinally extending raised edge portion of the groove being such as to effectively engage the latching element in the groove in all relative positions therealong, and a transversally extending raised edge portion bounding the groove to form a stop for the latching element, when the opening element is opened to the maximum extent permitted by the catch assembly.
 3. An adjustable catch assembly according to claim 1 wherein the catch unit has an open gap for receiving the catch bar, respective limb pOrtions on said catch unit facing respective grooves provided in the catch bar, one of said latching elements being mounted on each limb portion and having such length as to restrict the effective width of the gap to a magnitude less than the height of the wall means which contributes to preventing the latching elements from leaving the grooves, the cross section of the latching elements being so adjusted as to permit said elements to slide in the groove and to be inserted into the latching positions.
 4. An adjustable catch assembly according to claim 1 wherein the groove extending along the catch bar is defined on one long side by a comb-like wall including adjacent spaced teeth facing inwardly towards the groove and forming the latching positions between adjacent teeth.
 5. An adjustable catch assembly according to claim 3 wherein the gap between the limb members of the catch unit has a width which corresponds substantially to the thickness of the catch bar.
 6. An adjustable catch assembly according to claim 1 wherein said means enabling the catch bar to be engaged by the latching element includes a wedge-like member on said catch bar positioned to force the latching element resiliently when inserting the catch bar into said gap, until said latching element has passed into the groove.
 7. An adjustable catch assembly according to claim 6 wherein said wedge-shaped member is located adjacent the end of the catch bar which is connected to the fixed frame, said wedge-shaped member terminating substantially in a plane extending parallel with a plane passing through the pivotal axis of the catch bar to said frame and located at a distance from said plane in a direction towards the other end of the catch bar.
 8. An adjustable catch assembly according to claim 1 wherein said means for releasing the latching element from the catch bar is constituted by a recess in said wall means through which the latching element can pass to enable the catch bar to be disconnected from the catch unit.
 9. An adjustable catch assembly according to claim 8 comprising a threshold at the bottom of the groove which renders it necessary for the latching element to yield in order to leave the groove through the recess so as to release the catch bar from the catch unit.
 10. An adjustable catch assembly according to claim 4 in which the catch bar is provided with one said groove in two opposing long sides thereof, said wall means including a raised portion opposite each of the comb-like walls for said two grooves, said catch unit having an open gap for receiving the catch bar, respective limb portions on said catch unit facing respective grooves provided in the catch bar, one of said latching elements being mounted on each limb portion and having such length as to restrict the effective width of the gap to a magnitude less than the height of said wall means to prevent the latching elements from leaving the grooves, the cross section of the latching elements being so adjusted as to permit said elements to slide in the groove and to be inserted into the latching positions.
 11. An adjustable catch assembly according to claim 10 wherein said means for releasing the latching element from the catch bar is constituted by a recess in each said raised portion enabling passage therethrough of the latching elements for disconnection of the catch bar for the catch unit.
 12. An adjustable catch assembly according to claim 11 wherein said means enabling the catch bar to be engaged by the latching element comprises a wedge-shaped member on said raised portions to enable engagement of the catch bar with the catch unit.
 13. An adjustable catch assembly according to claim 12 wherein the catch bar comprises a knee-shaped portion and a straight portion, which form an angle with each other, the knee-shaped portion having a pivotal connection to the fixed frame and holding the wedge-shaped member at a distance from said pivotal connection to enable the wedge-shaped members to be engaged with respectivE latching elements.
 14. An adjustable catch assembly according to claim 4 comprising thresholds on said catch bar at the entrances of said latching positions between adjacent teeth of the comb-like wall which force the latching element to yield laterally when said element is moved into said latching positions.
 15. An adjustable catch assembly according to claim 1 wherein the catch bar and the catch unit are made from a plastic material.
 16. An adjustable catch assembly according to claim 1 wherein said latching element is integrally formed with the catch unit and made from the same plastic material, said plastic material being resilient.
 17. An adjustable catch assembly according to claim 1 wherein said latching element has a squared-off cross section to oppose disengagement thereof from the catch bar. 